1. Field of the Invention
The present invention relates to hoppers for mining trucks and aggregates in general, and the construction thereof.
2. Description of the Related Art
As we know, there are different types, designs and shapes of hoppers for mining trucks and aggregates, in general, that are used to transport materials or ores of various grain sizes, particle sizes and densities, which makes the amount of cargo or tonnage for a same volume to vary depending on this latter parameter. The materials they are made of are in general structural steels and, in some cases, non-abrasive steels, depending on the application and loading system. This latter point varies from task to task, giving a better or worse condition based on the loading of material. Such is the case of unloading through a chute door or gate, which is a rather gradual and controlled loading, as opposed to a shock loading, such as in the case of a front loader that projects the load through the sides of the truck, thereby falling on the loading area or the opposite side of the hopper without the equipment operator's vision. This causes extensive damage to the welds used to join the sides and the floor or front floor.
According to the above, sturdier hoppers are needed due to current conditions and trends of mining, which are targeted at larger and high load capacity equipment with greater availability of equipment for maintenance. This requires high capacity and resistance hoppers, thus requiring a greater number of structures or materials that make it more resistant, and/or a greater thickness to resist shocks and increase thicknesses in order to improve availability as a result of wearing of the plates which are in contact with the material, and slippage of the aggregates at the time of purging.
The current requirements for these loading components or hoppers demand that they are more robust by increasing their own weight with a decrease in the weight of the transported material by removing load capacity from the equipment (trucks). On the other hand, if a lighter hopper is made, i.e., by sacrificing thicknesses and materials of their structure, more frequent maintenances or replacements are needed or generated, and a decline in the availability of equipment due to frequent maintenance is confronted. Both scenarios are not what users are looking for. Rather, users desire a balance of load, shock and abrasion resistant in a light hopper having a greater availability respect to corrective maintenances.
The present invention is based on the use of technologically advanced or latest generation elements to be able to meet the demand of a greater load capacity and a longer service life due to the floor abrasion, satisfying the availability requirement of the client and the objectives set by the current market.
To meet the resistance and availability requirements, currently there are special steels, which are structurally more resistant ranging from 300 megapascals (MPa) to 700 MPa, depending on the type and origin. In contrast to the related art, the present invention proposes to (1) use steels with improved mechanical properties, (2) make a structure with an equal or greater resistance without increasing the thicknesses of the materials, since their densities do not vary much, and (3) create a design with the computer design methods and tools available in the market, thereby simplifying the structure by virtually analyzing the same in a quick and safe manner. This will allow the making of folded steels in critical areas of the hopper, thereby making it more resistant. In order to create these folds, more powerful and accurate equipment are required, forcing the use of high capacity folding technology and CNC (computer numerical control) controls. Also, given the size of the steel pieces, more power is required to fold them due to their special properties.
On the other hand, to prevent abrasive wearing, abrasion resistant steels are used. Such steels have hardness ranging from current 200 Brinell to 450 and/or 500 or more, with the capacity to significantly increase service life from wearing. However, such steels also have resistances ranging from 800 MPa to 1400 MPa and more, having more reason to use equipment more robust than traditional ones. As mentioned above, this allows the offering of a highly resistant and available product for production, but with a low weight in its structure. This allows a greater amount of load to be transported, and decreases the amount of fuel consumption, which, in large equipment can be very expensive.
Traditional manufacturing of hoppers is based on heavy structures with standard market folds or beams. In some cases there are special materials in terms of design, but they do not meet the above objectives. In the case of light hoppers, they have a lower weight in order to not affect the truck capacity. However, such hoppers have a shorter service life as a result of shocks and/or abrasion forcing to stop the equipment for more frequent maintenances.
In the case of non-abrasive steel applications, these are applied in their natural form as unfolded plates given their high resistance properties and the difficulty in making them with standard methods.
Accordingly, there is a need for an improved hopper for mining trucks and aggregates that use steels with improved mechanical properties, comprise a structure with an equal or greater resistance without increasing the thicknesses of the materials, since their densities do not vary much, and are designed using the computer design methods and tools available in the market, thereby simplifying the structure by virtually analyzing the same in a quick and safe manner. Further, there is also a need for an improved hopper which prevents the accumulation of material due to the wide radius of folding of the base plate in the areas of the floor with the front and the floor with the sides.